The objective of this research is to better understand the perception of complex auditory stimuli. The aim of the present research plan is to study the detectability of temporal synchrony for broad-band stimuli. The goal is to determine the locus of the mechanism(s) that mediate synchrony detection, and to apply that information to the perception of naturally occurring sounds such as speech and music. The experimental paradigm requires that listeners discriminate between simultaneously presented bands of noise that have envelopes that are either synchronous or asynchronous. Three experimental manipulations allow the determination of the locus of the discrimination mechanism(s). (1) Noise Masking. Judiciously chosen maskers will prevent listeners from extracting information about synchrony from frequency regions other than those containing the experimental bands. (2) Dichotic Synchrony Perception. Presenting the bands of noise to different ears will prevent listeners from relying on peripheral interactions for information concerning synchrony. Together, the masking and dichotic experiments will indicate whether synchrony detection depends on the comparison of information extracted from independent critical bands rather than information extracted from a single critical band. (3). Dichotic Masking. The effect of presenting different maskers to different ears will indicate the locus of the mechanism responsible for synchrony detection relative to the binaural auditory system. Examining the detection of envelope synchrony affords an opportunity to examine both peripheral auditory processes and more global central auditory processes. The basic information concerning temporal auditory processes that will result from this plan of study may provide a basis for the diagnosis and treatment for auditory impairment.